8-[2-(2-Pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA), which is a linoleic acid derivative, is a compound having a long-term enhancing action on synapse transmission efficiency, which can delay metabolism in the body and can maintain stable LTP (long-term potentiation)-like enhancement of synapse transmission (patent document 1).
Some reports have also been documented as regards DCP-LA. For example, it has been reported that DCP-LA activates PKC-ε selectively and directly (non-patent document 1), DCP-LA improves cognitive dysfunction of senescence accelerated mouse (non-patent document 2), DCP-LA increases release of γ aminobutyric acid from hippocampus nerve cells (non-patent document 3), DCP-LA improves cognitive dysfunction of amyloid β peptide or scopolamine-treated rat (non-patent document 4), and DCP-LA promotes hippocampal synaptic transmission with α7 nicotinic acetylcholine receptor expressed in glutamatergic presynaptic cell as a target (non-patent document 5). Furthermore, it has been reported in recent years that DCP-LA has an action to suppress nerve cell death induced by oxidative stress (patent document 2).
On the other hand, elastin fiber is one kind of connective tissue fibers of extracellular matrix distributed in almost all systemic organs and tissues, including blood vessel, ligament, lung and skin in the body of mammals such as human and the like, fish and the like, is formed by crosslinking of stretchable α-helix structure, and is known to play an important role in the maintenance of tissue flexibility.
The skin consists of epidermis, corium, and subcutaneous tissue. Epidermis protects body from outside drying and foreign substance, subcutaneous tissue reduces impact from the outside by subcutaneous fat and the like, and corium is constituted of fibroblast and corium extracellular matrix located outside these cells and supporting the skin structure, and plays an important role in the maintenance of skin structure.
The phenomena said to be the aging of the skin such as formation of wrinkles, dullness, disappearance of texture, decrease in elasticity of the skin are partly caused by a decreased ability to produce elastin fiber and the like due to the proliferative capacity of fibroblast which became lower by aging. It is also said that exposure of skin to UV, remarkable drying of air, outside stimulation such as excessive skin wash and the like, and the like cause decomposition of elastin fiber, which in turn results in the appearance of symptoms of rough skin, skin aging and the like caused by wrinkle formation, dullness, disappearance of texture, low elasticity and the like.
Therefore, it is effective for the prevention of aging of skin such as wrinkle, flabbiness and the like to prevent decomposition of elastin fiber or promote synthesis and regeneration of elastin fiber. However, a medicament that promotes regeneration and synthesis of elastin fiber is not known at present.